Arc-Related Origin of Volcaniclastic Sequences in the Misis Complex, Southern Turkey

The Miocene ophiolitic mélange-flysch association of the Misis Complex in southern Turkey contains three main units of clastic sediments that exhibit abundant acidic, mafic, and ultramafic clasts of magmatic origin. These are: (a) mixed volcaniclastics (vitric, lithic, and crystal tuffs) from the "matrix" of the mélange; (b) volcaniclastics (vitric tuffs) from large bedded sedimentary olistoliths; and (c) turbiditic flysch sediments with an admixture of magmatic, metamorphic and sedimentary clasts. Chemical and petrographie data suggest that magmatic clasts within the volcaniclastic sediments (units a and b) were derived from two main sources: an acidic calc-alkali volcanic arc and a back-arc ophiolite complex, now represented by basalt pillow lavas and ultramafic blocks within the mélange. The turbiditic flysch sediments (unit c) represent the accumulated debris of the denuded acidic arc, together with ophiolitic material derived via dismemberment and tectonic erosion of the back-arc basin crust. Chemical data indicate that the ophiolitic source, however, did not come into prominence until the late Middle Miocene.